Merge pull request #5 from wioletowa/add-sharednd

feat: add whyoolw/sharednd — auto DND while screen sharing
2026-07-14 21:33:21 -04:00
parent 52e1365ca6 ca3f8dce74
commit 7b4ee77789
5 changed files with 283 additions and 0 deletions
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+# ShareDND
+
+Automatic Do Not Disturb while the screen is being shared.
+
+When the first screencast starts (any app sharing via the portal — Discord,
+OBS, browsers, `niri msg action set-dynamic-cast-*`, ...), notification DND is
+enabled. When the last screencast stops, notifications come back.
+
+## How it works
+
+- A headless service follows `niri msg -j event-stream` and reacts to
+  `CastsChanged` / `CastStartedOrChanged` / `CastStopped` events — no polling.
+- On every cast event it re-queries `niri msg -j casts` as the authoritative
+  state, so missed or reordered events cannot desync it. The stream is wrapped
+  in a shell retry loop and resends full state on reconnect.
+- Stop transitions are debounced by ~1 second: switching what is being shared
+  produces a stop/start event pair, which the debounce collapses — DND does
+  not flap, and the stop/start race cannot drop ownership.
+- DND is toggled through the host IPC (`noctalia msg notification-dnd-set`),
+  so the usual OSD feedback appears.
+
+## Ownership rules
+
+- If DND was **already on** before sharing started, the plugin leaves it on
+  after sharing ends (it never took ownership). The
+  "Always disable DND after sharing" setting overrides this.
+- If DND was enabled manually *during* sharing while the plugin owned it, it
+  will still be turned off when sharing ends (the plugin cannot tell the
+  difference).
+
+## Settings
+
+- **Only active streams** — count only casts with `is_active: true`. Off by
+  default: any open screencast session (even paused or showing nothing) keeps
+  DND on.
+- **Always disable DND after sharing** — force DND off when sharing ends,
+  regardless of its state before sharing started.
+
+## Requirements & limitations
+
+- Requires **niri** (detection is niri IPC). Detection only starts inside a
+  niri session (`NIRI_SOCKET` set and the `niri` binary in `PATH`); on other
+  compositors the service is inert and spawns no processes.
+- Disabling or reloading the plugin mid-share while it owns DND turns DND
+  back off (`onExit` cleanup).
@@ -0,0 +1,41 @@
+# ShareDND — automatic Do Not Disturb while the screen is being shared.
+#
+# A headless [[service]] follows `niri msg -j event-stream` and re-queries
+# `niri msg -j casts` on every Cast* event. When the first screencast
+# appears, notification DND is enabled through the host IPC
+# (notification-dnd-set); when the last one disappears, DND is restored.
+# If DND was already on before sharing started, the plugin does not take
+# ownership and leaves it on afterwards (configurable). Detection only
+# starts inside a niri session (NIRI_SOCKET + niri binary present); on
+# other compositors the service is inert and spawns nothing.
+#
+# External requirements: niri (screencast events come from niri IPC).
+
+id = "whyoolw/sharednd"
+name = "ShareDND"
+version = "1.1.0"
+min_noctalia = "5.0.0"
+author = "whyoolw"
+license = "MIT"
+dependencies = ["niri"]
+tags = ["privacy", "niri"]
+icon = "screen-share"
+description = "Enables notification Do Not Disturb while the screen is shared (niri screencast) and turns notifications back on when sharing stops. Requires niri."
+
+[[setting]]
+key = "only_active"
+type = "bool"
+label_key = "settings.only_active.label"
+description_key = "settings.only_active.description"
+default = false
+
+[[setting]]
+key = "always_off_after"
+type = "bool"
+label_key = "settings.always_off_after.label"
+description_key = "settings.always_off_after.description"
+default = false
+
+[[service]]
+id = "service"
+entry = "service.luau"
@@ -0,0 +1,188 @@
+-- ShareDND service: watches niri screencasts and toggles notification
+-- Do Not Disturb while the screen is being shared.
+--
+-- Detection is event-driven: a persistent `niri msg -j event-stream` runs
+-- under runStream, wrapped in a shell retry loop because the stream API has
+-- no exit notification. Any Cast* event triggers a re-query of
+-- `niri msg -j casts`, which is the authoritative state, so no per-event
+-- bookkeeping is needed and reconnects re-sync for free (the stream sends
+-- the full current state, including CastsChanged, on connect).
+--
+-- Stop transitions are debounced by STOP_DEBOUNCE seconds. Switching what is
+-- being shared surfaces as a stop/start event pair; acting on the stop
+-- immediately would race the follow-up status query (the async `off` can
+-- land after the query already read DND as on), dropping ownership and
+-- leaving DND off for the rest of the new sharing session. The debounce
+-- collapses the pair into no transition, and also keeps DND from flapping.
+
+local STOP_DEBOUNCE = 1.0
+
+local function cfg(key)
+  return noctalia.getConfig(key)
+end
+
+-- debounced sharing state that the DND logic acts on
+local sharingActive = false
+-- true when this plugin enabled DND (and therefore owns turning it off)
+local dndSetByUs = false
+
+-- raw state from the last casts query + pending debounced stop deadline
+local rawActive = false
+local stopDeadline = nil -- os.clock() timestamp, nil when no stop is pending
+
+local queryInFlight = false
+local queryDirty = false
+
+local function countCasts(json)
+  local needle = cfg("only_active") and '"is_active":true' or '"session_id":'
+  local n = 0
+  local pos = 1
+  while true do
+    local s, e = json:find(needle, pos, true)
+    if not s then
+      break
+    end
+    n = n + 1
+    pos = e + 1
+  end
+  return n
+end
+
+local function setDnd(on, cb)
+  noctalia.runAsync("noctalia msg notification-dnd-set " .. (on and "on" or "off"), function(res)
+    local ok = res ~= nil and res.exitCode == 0
+    if not ok then
+      noctalia.log("sharednd: notification-dnd-set failed")
+    end
+    if cb then
+      cb(ok)
+    end
+  end)
+end
+
+local function onSharingStarted()
+  noctalia.runAsync("noctalia msg notification-dnd-status", function(res)
+    if not sharingActive then
+      return -- sharing already ended while the status query was in flight
+    end
+    if res == nil or res.exitCode ~= 0 then
+      noctalia.log("sharednd: notification-dnd-status failed")
+      return
+    end
+    if (res.stdout or ""):match("^%s*on") then
+      -- DND was already on (enabled manually) — don't take ownership.
+      dndSetByUs = false
+      noctalia.log("sharednd: sharing started, DND already on")
+    else
+      setDnd(true, function(ok)
+        dndSetByUs = ok
+        if ok then
+          noctalia.log("sharednd: sharing started, DND enabled")
+          if not sharingActive then
+            -- sharing ended while the set was in flight — undo
+            setDnd(false)
+            dndSetByUs = false
+          end
+        end
+      end)
+    end
+  end)
+end
+
+local function onSharingStopped()
+  if dndSetByUs or cfg("always_off_after") then
+    setDnd(false)
+    noctalia.log("sharednd: sharing stopped, DND disabled")
+  else
+    noctalia.log("sharednd: sharing stopped, DND left as-is")
+  end
+  dndSetByUs = false
+end
+
+local function applyState(activeCount)
+  rawActive = activeCount > 0
+  if rawActive then
+    -- A restart within the debounce window cancels the pending stop, so a
+    -- stop/start pair from switching casts is no transition at all.
+    stopDeadline = nil
+    if not sharingActive then
+      sharingActive = true
+      onSharingStarted()
+    end
+  elseif sharingActive and stopDeadline == nil then
+    stopDeadline = os.clock() + STOP_DEBOUNCE
+  end
+end
+
+local function queryCasts()
+  if queryInFlight then
+    queryDirty = true
+    return
+  end
+  queryInFlight = true
+  noctalia.runAsync("niri msg -j casts", function(res)
+    queryInFlight = false
+    if res ~= nil and res.exitCode == 0 and res.stdout ~= nil then
+      applyState(countCasts(res.stdout))
+    end
+    if queryDirty then
+      queryDirty = false
+      queryCasts()
+    end
+  end)
+end
+
+local function onEventLine(line)
+  -- Matches CastsChanged / CastStartedOrChanged / CastStopped. The casts
+  -- query is authoritative, so a rare false positive (a window title
+  -- containing '"Cast') only costs one extra query.
+  if line:find('"Cast', 1, true) then
+    queryCasts()
+  end
+end
+
+-- Host-driven tick (~250 ms): commits a pending stop once the debounce
+-- window has passed without sharing resuming.
+function update()
+  if stopDeadline ~= nil and os.clock() >= stopDeadline then
+    stopDeadline = nil
+    if sharingActive and not rawActive then
+      sharingActive = false
+      onSharingStopped()
+    end
+  end
+end
+
+-- Called by the host on plugin disable/reload. The callback-less runAsync
+-- spawns a detached process, so it survives the VM teardown.
+function onExit()
+  if dndSetByUs then
+    noctalia.runAsync("noctalia msg notification-dnd-set off")
+  end
+end
+
+-- Boot. `niri msg` needs the niri binary and NIRI_SOCKET (set only inside a
+-- niri session), so gate detection on both instead of spawning a retry loop
+-- that can never succeed on other compositors.
+local niriSocket = noctalia.getenv("NIRI_SOCKET")
+if niriSocket == nil or niriSocket == "" then
+  -- Expected on other compositors: stay silent and spawn nothing.
+  noctalia.log("sharednd: no NIRI_SOCKET, not a niri session — detection disabled")
+elseif not noctalia.commandExists("niri") then
+  -- Inside a niri session but the binary is unreachable — worth a warning.
+  noctalia.notifyError(noctalia.tr("notify.no_niri_title"), noctalia.tr("notify.no_niri_body"))
+  noctalia.log("sharednd: NIRI_SOCKET set but niri not in PATH — detection disabled")
+else
+  -- The process group is killed on plugin disable, taking the shell loop and
+  -- the stream down with it. That cleanup does not run when the host dies
+  -- hard (crash, session logout), so the loop also exits on its own once the
+  -- parent is gone or the niri socket disappears — otherwise orphaned loops
+  -- would keep respawning `niri msg` every 3 s across sessions.
+  local loop = 'P=$PPID; while kill -0 "$P" 2>/dev/null && [ -S "$NIRI_SOCKET" ]; do'
+    .. " niri msg -j event-stream 2>/dev/null; sleep 3; done"
+  if not noctalia.runStream(loop, onEventLine) then
+    noctalia.log("sharednd: failed to start niri event-stream")
+  end
+  -- Safety net in case the initial CastsChanged is ever missed.
+  queryCasts()
+end
@@ -0,0 +1,9 @@
+{
+  "title": "ShareDND",
+  "settings.only_active.label": "Only active streams",
+  "settings.only_active.description": "Count only screencasts that are actively streaming. When off, any open screencast session (even one paused or showing nothing) keeps Do Not Disturb enabled.",
+  "settings.always_off_after.label": "Always disable DND after sharing",
+  "settings.always_off_after.description": "Turn Do Not Disturb off when sharing ends even if it was already enabled before sharing started. When off, DND is only disabled if this plugin enabled it.",
+  "notify.no_niri_title": "ShareDND: niri not found",
+  "notify.no_niri_body": "This looks like a niri session (NIRI_SOCKET is set), but the niri binary is not in PATH, so screen sharing cannot be detected."
+}